Method and System for Training an Ethernet Channel Based on an Active Channel to Support Energy Efficient Ethernet Networks

ABSTRACT

An Ethernet link may comprise silent and active channels and may support energy efficient Ethernet communication. Training parameters from the one or more active channels may be utilized for determining and/or adjusting training parameters for silent channels prior to activation. Training parameters for silent channels may be determined based on copying training parameters from active channels. Determination of training parameters for silent channels may be based on a weighted average of the active channel training parameters. A delta between active channel training parameters from a prior time and subsequent time may be utilized to determine a correction factor for adjusting training parameters for a silent channel from a prior time. Silent channels may be adjusted based on active channel training parameters and then subsequently may be trained. Training parameters may be adjusted for one or more of an echo canceler, a near-end crosstalk canceler and a far-end canceler.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

This application is a continuation of U.S. Non-Provisional applicationSer. No. 12/042,139, filed Mar. 4, 2008, which makes reference to andclaims priority to U.S. Provisional Application Ser. No. 60/979,433,filed on Oct. 12, 2007. U.S. Non-Provisional application Ser. No.12/042,139 is a continuation-in-part of U.S. Non-Provisional applicationSer. No. 11/859,429 (Now U.S. Pat. No. 8,218,567), filed Sep. 21, 2007,which makes reference to and claims priority to U.S. ProvisionalApplication Ser. No. 60/917,870, filed on May 14, 2007, and U.S.Provisional Application Ser. No. 60/894,240, filed on Mar. 12, 2007.Each of the above-identified applications is hereby incorporated hereinby reference in its entirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to networking. Morespecifically, certain embodiments of the invention relate to a methodand system for training an Ethernet channel based on an active channelto support energy efficient Ethernet networks.

BACKGROUND OF THE INVENTION

With the increasing popularity of electronics such as desktop computers,laptop computers, and handheld devices such as smart phones and PDA's,communication networks, and in particular Ethernet networks, arebecoming an increasingly popular means of exchanging data of varioustypes and sizes for a variety of applications. In this regard, Ethernetnetworks are increasingly being utilized to carry, for example, voice,data, and multimedia. Accordingly more and more devices are beingequipped to interface to Ethernet networks.

As the number of devices connected to data networks increases and higherdata rates are required, there is a growing need for new transmissiontechnologies which enable higher data rates. Conventionally, however,increased data rates often result in significant increases in powerconsumption. In this regard, as an increasing number of portable and/orhandheld devices are enabled for Ethernet communications, battery lifemay be a concern when communicating over Ethernet networks. Accordingly,reducing power consumption when communicating over Ethernet networks isbecoming popular.

New transmission technologies enable higher transmission rates overcopper cabling infrastructures. Various efforts exist in this regard,including technologies that enable transmission rates that may evenreach 100 Gigabit-per-second (Gbps) data rates over existing cabling.For example, the IEEE 802.3 standard defines the (Medium Access Control)MAC interface and physical layer (PHY) for Ethernet connections at 10Mbps, 100 Mbps, 1 Gbps, and 10 Gbps data rates over twisted-pair coppercabling 100 m in length. With each 10× rate increase more sophisticatedsignal processing is required to maintain the 100 m standard cablerange. Non-standard transmission rates comprise 2.5 Gbps as well as 5Gbps.

The specification for 10 Gigabit-per-second (Gbps) Ethernettransmissions over twisted-pair cabling (10 GBASE-T) is intended toenable 10 Gbps connections over twisted-pair cabling at distances of upto 182 feet for existing cabling, and at distances of up to 330 feet fornew cabling, for example. To achieve full-duplex transmission at 10 Gbpsover four-pair twisted-pair copper cabling, elaborate digital signalprocessing techniques are needed to remove or reduce the effects ofsevere frequency-dependent signal attenuation, signal reflections,near-end and far-end crosstalk between the four pairs, and externalsignals coupled into the four pairs either from adjacent transmissionlinks or other external noise sources. New IEEE cabling specificationsare being considered for 40 Gbps and 100 Gbps rates.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with the present invention as set forth inthe remainder of the present application with reference to the drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an Ethernet connection between alocal link partner and a remote link partner, in accordance with anembodiment of the invention.

FIG. 2 is a block diagram illustrating an exemplary Ethernet overtwisted pair PHY device architecture, in accordance with an embodimentof the invention.

FIG. 3 is a block diagram illustrating training an Ethernet channelbased on active channels, in accordance with an embodiment of theinvention.

FIG. 4 is a flow chart illustrating exemplary steps for training anEthernet channel based on an active channel, in accordance with anembodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention may be found in a method and systemfor training an Ethernet channel based on an active channel to supportenergy efficient Ethernet networks. In various embodiments of theinvention, an Ethernet link may comprise a plurality of channels whereinone or more of the channels may be active and one or more of thechannels may be silent or in a lower power state. In this regard, silentor lower power channels may be activated according to traffic demand.Functionality within Ethernet link partners that may supporttransitioning between active channel states and lower power states mayenable energy efficient Ethernet communication. During active and/orlower power operations Ethernet link partners may train and/or configureone or more parameters and/or circuits for one or more channels on anEthernet link. For example, parameters and/or circuits may be adjustedto account for variable operating conditions such as type of cablingand/or length of cabling or for environmental conditions such astemperature and/or electromagnetic coupling. Communication via activechannels may need to be interrupted while training activity isperformed. Channels in a silent or lower power state may refreshparameters and/or circuits from time to time or prior to carryingtraffic. Accordingly, parameters and/or circuits for one or morechannels in a silent or lower energy state may be configured based ontraining parameters and/or circuits from one or more active channels forone or more of echo cancelers, near-end crosstalk cancelers and/orfar-end crosstalk cancelers for example.

The silent channel training parameters may be determined based on a copyof active channel training parameters, a weighted average of activechannel training parameters, and/or a delta between active channeltraining parameters at a prior time and the active channel trainingparameters at a subsequent time. In this regard, training parametersfrom the silent channels may be modified based on the delta betweenactive channel training parameters at a prior time and the activechannel training parameters at a subsequent time. For example, acorrection factor for modifying the silent channel training parametersmay be based on the delta between active channel training parameter froma prior time and the active channel training parameter at a subsequenttime. The silent channel training parameters may be configured based onthe active channel training parameters and may be subsequently trained.The training parameters may be configured for one or more of an echocancelers, near-end crosstalk cancelers and/or far-end crosstalkcancelers for example.

FIG. 1 is a block diagram illustrating an Ethernet connection between alocal link partner and a remote link partner, in accordance with anembodiment of the invention. Referring to FIG. 1, there is shown asystem 100 that comprises a local link partner 102 and a remote linkpartner 104. The local link partner 102 and the remote link partner 104may communicate via a cable 112. In an exemplary embodiment of theinvention, the cable 112 may comprise up to four or more channels, eachof which may, for example, comprise an unshielded twisted pair (UTP).The local link partner 102 and the remote link partner 104 maycommunicate via two or more channels comprising the cable 112. Forexample, Ethernet over twisted pair standards 10 BASE-T and 100 BASE-TXmay utilize two pairs of UTP while Ethernet over twisted pair standards1000 BASE-T and 10 GBASE-T may utilize four pairs of UTP. In thisregard, however, aspects of the invention may enable varying the numberof physical channels via which data is communicated.

In an exemplary embodiment of the invention, the link partners 102and/or 104 may comprise a twisted pair PHY capable of operating at oneor more standard rates such as 10 Mbps, 100 Mbps, 1 Gbps, and 10 Gbps(10 BASE-T, 100 GBASE-TX, 1 GBASE-T, and/or 10 GBASE-T); potentiallystandardized rates such as 40 Gbps and 100 Gbps; and/or non-standardrates such as 2.5 Gbps and 5 Gbps.

In an exemplary embodiment of the invention, the link partners 102and/or 104 may comprise a backplane PHY capable of operating at one ormore standard rates such as 10 Gbps (10 GBASE-KX4 and/or 10 GBASE-KR);and/or non-standard rates such as 2.5 Gbps and 5 Gbps.

The local link partner 102 may comprise a host 106 a, a medium accesscontrol (MAC) controller 108 a, and a PHY device 104 a. The remote linkpartner 104 may comprise a host 106 b, a MAC controller 108 b, and a PHYdevice 110 b. Notwithstanding, the invention is not limited in thisregard. In various embodiments of the invention, the link partner 102and/or 104 may comprise, for example, computer systems or audio/video(A/V) enabled equipment. In this regard, A/V equipment may, for example,comprise, a microphone, an instrument, a sound board, a sound card, avideo camera, a media player, a graphics card, or other audio and/orvideo device. Additionally, the link partners 102 and 104 may be enabledto utilize Audio/Video Bridging and/or Audio/video bridging extensions(collectively referred to herein as AVB) for the exchange of multimediacontent and associated control and/or auxiliary data.

The PHY devices 110 a and 110 b may each comprise suitable logic,circuitry, and/or code that may enable communication, for example,transmission and reception of data, between the local link partner 102and the remote link partner 104. The PHY devices 110 a and 110 b maysupport, for example, Ethernet operations. The PHY device s 110 a and110 b may enable communications, such as 10 Mbps, 100 Mbps, 1000 Mbps(or 1 Gbps), 2.5 Gbps, 4 Gbps, 5 Gbps, 10 Gbps, 40 Gbps or 100 Gbps, forexample. In this regard, the PHY devices 110 a and 110 b may supportstandard-based data rates and/or non-standard data rates. Moreover, thePHY devices 110 a and 110 b may support standard Ethernet link lengthsor ranges of operation and/or extended ranges of operation. The PHYdevices 110 a and 110 b may enable communication between the local linkpartner 102 and the remote link partner 104 by utilizing a linkdiscovery signaling (LDS) operation that enables detection of activeoperations in the other link partner. In this regard the LDS operationmay be configured for supporting a standard Ethernet operation and/or anextended range Ethernet operation. The PHY devices 110 a and 110 b mayalso support autonegotiation for identifying and selecting communicationparameters such as speed and duplex mode.

In various embodiments of the invention, the PHY devices 110 a and 110 bmay comprise suitable logic, circuitry, and/or code that may enabletransmission and/or reception at a high(er) data rate in one directionand transmission and/or reception at a low(er) data rate in the otherdirection. For example, the local link partner 102 may comprise amultimedia server and the remote link partner 104 may comprise amultimedia client. In this regard, the local link partner 102 maytransmit multimedia data, for example, to the remote partner 104 athigh(er) data rates while the remote link partner 104 may transmitcontrol or auxiliary data associated with the multimedia content atlow(er) data rates. In addition, a change in rate such as stepping up inrate or stepping down in rate may occur asymmetrically among the PHYdevices 110 a and/or 110 b which may support energy efficient Ethernet.For example, the PHY 110 a may change rate based on a change of rate in110 b however, PHY 110 a may change to a different rate than PHY 110 b.Moreover, the PHY devices 110 a and 110 b may change rates independentof each other, for example, one PHY may change rate while the other doesnot change rate.

The data transmitted and/or received by the PHY devices 110 a and 110 bmay be formatted in accordance with the well-known OSI protocolstandard. The OSI model partitions operability and functionality intoseven distinct and hierarchical layers. Generally, each layer in the OSImodel is structured so that it may provide a service to the immediatelyhigher interfacing layer. For example, layer 1, or physical layer, mayprovide services to layer 2 and layer 2 may provide services to layer 3.The data transmitted may comprise frames of Ethernet media independentinterface (MII) data which may be delimited by start of stream and endof stream delimiters, for example. The data transmitted may alsocomprise IDLE symbols that may be communicated between frames of data,during inter frame gap (IFG)).

In an exemplary embodiment of the invention illustrated in FIG. 1, thehosts 106 a and 106 b may represent layer 2 and above, the MACcontrollers 108 a and 108 b may represent layer 2 and above and the PHYdevices 110 a and 110 b may represent the operability and/orfunctionality of layer 1 or the physical layer. In this regard, the PHYdevices 110 a and 110 b may be referred to as physical layertransmitters and/or receivers, physical layer transceivers, PHYtransceivers, PHYceivers, or PHY, for example. The hosts 106 a and 106 bmay comprise suitable logic, circuitry, and/or code that may enableoperability and/or functionality of the five highest functional layersfor data packets that are to be transmitted over the cable 112. Sinceeach layer in the OSI model provides a service to the immediately higherinterfacing layer, the MAC controllers 108 a and 108 b may provide thenecessary services to the hosts 106 a and 106 b to ensure that packetsare suitably formatted and communicated to the PHY devices 110 a and 110b. During transmission, each layer may add its own header to the datapassed on from the interfacing layer above it. However, duringreception, a compatible device having a similar OSI stack may strip offthe headers as the message passes from the lower layers up to the higherlayers.

The PHY devices 110 a and 110 b may be configured to handle all thephysical layer requirements, which include, but are not limited to,packetization, data transfer and serialization/deserialization (SERDES),in instances where such an operation is required. Data packets receivedby the PHY devices 110 a and 110 b from MAC controllers 108 a and 108 b,respectively, may include data and header information for each of theabove six functional layers. The PHY devices 110 a and 110 b may beconfigured to encode data packets that are to be transmitted over thecable 112 and/or to decode data packets received from the cable 112.

The MAC controller 108 a may comprise suitable logic, circuitry, and/orcode that may enable handling of data link layer, layer 2, operabilityand/or functionality in the local link partner 102. Similarly, the MACcontroller 108 b may comprise suitable logic, circuitry, and/or codethat may enable handling of layer 2 operability and/or functionality inthe remote link partner 104. The MAC controllers 108 a and 108 b may beconfigured to implement Ethernet protocols, such as those based on theIEEE 802.3 standard, for example. Notwithstanding, the invention is notlimited in this regard.

The MAC controller 108 a may communicate with the PHY device 110 a viaan interface 114 a and with the host 106 a via a bus controllerinterface 116 a. The MAC controller 108 b may communicate with the PHYdevice 110 b via an interface 114 b and with the host 106 b via a buscontroller interface 116 b. The interfaces 114 a and 114 b correspond toEthernet interfaces that comprise protocol and/or link managementcontrol signals. The interfaces 114 a and 114 b may be multi-rateinterfaces and/or media independent interfaces (MII). The bus controllerinterfaces 116 a and 116 b may correspond to PCI or PCI-X interfaces.Notwithstanding, the invention is not limited in this regard.

In operation, PHY devices such as the PHY devices 110 a and 110 b mayconventionally transmit data via a fixed number of channels which mayresult in network links being underutilized for significant portions oftime. When the link partners 102 and 104 first establish a connection,they may exchange some preliminary information and/or training signals.In this regard, the link partners 102 and 104 may negotiate a data rate(e.g., 10 Gbps) and duplex mode (e.g., full-duplex) for communicatingwith each other. Additionally, in order to establish reliablecommunications, each of the link partners 102 and 104 may need to and/oradjust various parameters and/or circuitry to account for variables suchas the type of cabling over which data is being communicated andenvironmental conditions (e.g. temperature) surrounding the cabling.This process of configuring one or more circuits and/or parameters of anEthernet channel may be referred to as “training”. In this regard,“training” may adapt an Ethernet channel to current conditions such thatfunctions such as echo cancellation, far-end crosstalk cancellation, andnear-end crosstalk cancellation may be performed.

Training coefficients, parameters and/or circuitry may need to beperiodically refreshed or retrained. For example, channels which havebeen inactive for a period of time may need to be “retrained” such thatcircuitry and/or parameters, which may become outdated over time, arerefreshed in order to provide reliable data communications over thechannel(s).

FIG. 2 is a block diagram illustrating an exemplary Ethernet overtwisted pair PHY device architecture, in accordance with an embodimentof the invention. Referring to FIG. 2, there is shown a link partner 200which may comprises an Ethernet over twisted pair PHY device 202, a MACcontroller 204, a host 206, an interface 208, and a bus controllerinterface 210. The PHY device 202 may be an integrated device which maycomprise a physical layer block 212, one or more transmitters 214, oneor more receivers 220, a memory 216, a memory interface 218, one or moreinput/output interfaces 222 and channels 224.

The PHY device 202 may be an integrated device that may comprise aphysical layer block 212, one or more transmitters 214, one or morereceivers 220, a memory 216, a memory interface 218, and one or moreinput/output interfaces 222. The operation of the PHY device 202 may bethe same as or substantially similar to that of the PHY devices 110 aand 110 b disclosed in FIG. 1. In this regard, the PHY device 202 mayprovide layer 1 (physical layer) operability and/or functionality thatenables communication with a remote PHY device. Similarly, the operationof the MAC controller 204, the host 206, the interface 208, and the buscontroller 210 may be the same as or substantially similar to therespective MAC controllers 108 a and 108 b, hosts 106 a and 106 b,interfaces 114 a and 114 b, and bus controller interfaces 116 a and 116b as described in FIG. 1. The MAC controller 204 may comprise aninterface 204 a that may comprise suitable logic, circuitry, and/or codeto enable communication with the PHY device 202 via the interface 208.

The physical layer block 212 in the PHY device 202 may comprise suitablelogic, circuitry, and/or code that may enable operability and/orfunctionality of physical layer requirements. In this regard, thephysical layer block 212 may enable generating the appropriate linkdiscovery signaling utilized for establishing communication with aremote PHY device in a remote link partner. The physical layer block 212may communicate with the MAC controller 204 via the interface 208. Inone aspect of the invention, the interface 208 may be a mediaindependent interface (MII) and may be configured to utilize a pluralityof serial data lanes for receiving data from the physical layer block212 and/or for transmitting data to the physical layer block 212. Thephysical layer block 212 may be configured to operate in one or more ofa plurality of communication modes, where each communication mode mayimplement a different communication protocol. These communication modesmay include, but are not limited to, Ethernet over twisted pairstandards 10 BASE-T, 100 Base-TX, 1000 Base-T, 10 GBase-T, and othersimilar protocols. The physical layer block 212 may be configured tooperate in a particular mode of operation upon initialization or duringoperation. For example, auto-negotiation may utilize the FLP bursts toestablish a rate (e.g. 10 Mbps, 100 Mbps, 1000 Mbps, or 10 Gbps) andmode (half-duplex or full-duplex) for transmitting information.

The physical layer block 212 may be coupled to memory 216 through thememory interface 218, which may be implemented as a serial interface ora bus. The memory 216 may comprise suitable logic, circuitry, and/orcode that may enable storage or programming of information that includesparameters and/or code that may effectuate the operation of the physicallayer block 212. The parameters may comprise configuration data and thecode may comprise operational code such as software and/or firmware, butthe information need not be limited in this regard. Moreover, theparameters may include adaptive filter and/or block coefficients for useby the physical layer block 212, for example.

Each of the transmitters 214 a, 214 b, 214 c, 214 d may comprisesuitable logic, circuitry, and/or code that may enable transmission ofdata from the link partner 200 to a remote link partner via, forexample, the cable 112 in FIG. 1. The receivers 220 a, 220 b, 220 c, 220d may comprise suitable logic, circuitry, and/or code that may enablereceiving data from a remote link partner. Each of the transmitters 214a, 214 b, 214 c, 214 d and receivers 220 a, 220 b, 220 c, 220 d in thePHY device 202 may correspond to a channel that may comprise the cable112. In this manner, a transmitter/receiver pair may interface with eachof the channels 224 a, 224 b, 224 c, 224 d.

The input/output interfaces 222 may comprise suitable logic circuitry,and/or code that may enable the PHY device 202 to impress signalinformation onto a physical medium comprising a channel, for example atwisted pair channel comprising the cable 112 disclosed in FIG. 1.Consequently, the input/output interfaces 222 may, for example, provideconversion between differential and single-ended, balanced andunbalanced, signaling methods. In this regard, the conversion may dependon the signaling method utilized by the transmitter 214, the receiver220, and the type of medium comprising the channel. Accordingly, theinput/output interfaces 222 may comprise one or more baluns and/ortransformers and may, for example, enable transmission over a twistedpair. Additionally, the input/output interfaces 222 may be internal orexternal to the PHY device 202. In this regard, if the PHY device 202comprises an integrated circuit, then “internal” may, for example, referto being “on-chip” and/or sharing the same substrate. Similarly, if thePHY device 202 comprises one or more discrete components, then“internal” may, for example, refer to being on the same printed circuitboard or being within a common physical package.

In operation, the PHY device 202 may be enabled to transmit and receivesimultaneously over up to four or more physical links. Accordingly, thelink partner 200 may comprise a number of hybrids 226 corresponding tothe number of physical links. Each hybrid 226 may comprise suitablelogic, circuitry, and/or code that may enable separating transmitted andreceived signals from a physical link. For example, the hybrids maycomprise echo cancelers, far-end crosstalk (FEXT) cancelers, and/ornear-end crosstalk (NEXT) cancelers. Each hybrid 226 in the local linkpartner 300 may be communicatively coupled to an input/output interface222.

Due to the complex nature of the signal processing involved withfull-duplex communication at high data rates, various components of thelink partner 200 may be “trained” in order to provide reliablecommunications with a remote link partner. For example, the echocancelers, FEXT cancelers, and/or NEXT cancelers may comprise one ormore configuration parameters which may be determined based on factorscomprising, for example, on environmental conditions, distance to theremote link partner, and data rate. Accordingly, these configurationparameters may need to be configured upon establishing a connection to aremote link partner. Moreover, these configuration parameters may needto be periodically refreshed due to for example, environmental changes.In the event that one or more links 224 may be inactive for some amountof time, environmental conditions may change and training coefficientsand/or parameters may need to be updated prior to activating datatraffic on the link.

FIG. 3 is a block diagram illustrating training an Ethernet channelbased on active channels, in accordance with an embodiment of theinvention. Referring to FIG. 3 there is shown the link partners 300 aand 300 b which may communicate via one or more of the channels 324 a,324 b, 324 c, and 324 d.

The link partners 300 a and 300 b may be similar or substantially thesame as the link partner 200 described in FIG. 2 and the link partners102 and 104 described in FIG. 1.

Referring to FIG. 3, prior to time instant T=1, the channels 324 a, 324b, and 324 c are active, and thus their respective training parameters,TP1, TP2, TP3 are valid. In this regard, an ‘A’ subscript indicates thatTP1, TP2, and TP3 may be actively updated. On the other hand, prior totime instant T=1, the channel 324 d is silent and the trainingparameters, TP4, may be invalid (as indicated by the ‘x’ subscript). Attime instant T=1 the channel 324 d may transition from a lower powerstate to a higher power state for full bandwidth communication.Accordingly, one or more of the training parameters TP11, TP21, andTP31, may be utilized to determine TP41. In an exemplary embodiment ofthe invention, one of TP11, TP21, and TP31 may be used for TP41. Inanother exemplary embodiment of the invention, a combination (e.g. aweighted average) of TP11, TP21, and/or TP31 may be utilized todetermine TP41.

Although, the FIG. 3 depicts one channel being silent and subsequentlybecoming active, the invention is not so limited. In this regard,training parameters for any number of previously silent or low(er) powerchannels may be configured utilizing training parameters from at leastone active channel. Also, channels may emerge from a lower power stateand become active sequentially or in parallel. Additionally, in variousembodiments of the invention, a shortened training period may follow aninitialization of training parameters based on the training parametersof at least one active channel.

In operation, one or more channels 324 may be active and one or morechannels 324 may become active from a silent or lower power state basedon training information from the active channels and may avoid or reducedelay imposed by retraining. In this regard, when channels are silent,or placed into a low(er) power state, their coefficients and/orparameters configured during channel training may become stale or nolonger applicable. When a channel becomes active, the channel may needto be “re-trained” in order to establish reliable communications betweenthe link partners 300 a and 300 b via that channel. In some embodimentsof the invention, the coefficients and/or parameters for one or moresilent channels may be based on copies of coefficients from one or moreactive channels. In this regard, coefficients and/or parameters may becopied from one or more of the active channels to the one or morechannels going from a silent or lower power state to an active state.For example, coefficients and/or parameters from one of 324 a, 324 b or324 c may be copied to channel 324 d.

In other embodiments of the invention, coefficients and/or parametersfrom a plurality of active channels may be utilized to determinecoefficients and/or parameters for one or more channels going from asilent or lower power state to a higher power state. For example, aweighted average of the active channel coefficients and/or parametersmay be utilized. Moreover, in some embodiments of the invention, a deltabetween the coefficients and/or parameters on an active channel at aprior time and a subsequent time may be utilized as a correction factorto adjust the coefficients and/or parameters for a channel transitioningfrom a silent state to an active state. For example, coefficients and/orparameters from one or more of the active channels 324 a, 324 b and 324c may be recorded at or near the time when the channel 324 dtransitioned from active to silent (T=0) and again when the channel 324d is ready to transition from silent to active (T=1). The delta betweenthe two measurements at T=0 and T=1 on the one or more active channelsmay be utilized as a correction factor in adjusting the coefficientsand/or parameters for 324 d that have may have not been refreshed sincethe time that 324 d transitioned from active to silent at T=0. Ifparameters and/or circuits are not adequately updated, link partners mayperform full training activity to enable transitioning a channel from alower power state to a higher power state for carrying traffic. Fulltraining activity may take on the order of 100 ms or seconds. Inaccordance with an embodiment of the invention, the time to transitionfrom a lower power state to a higher power state may be reducedsignificantly since silent channels may not need to go through a fulltraining cycle.

FIG. 4 is a flow chart illustrating exemplary steps for training anEthernet channel based on an active channel, in accordance with anembodiment of the invention. Referring to FIG. 4, after start step 402,in step 404, coefficients on active channels 324 a, 324 b and/or 324 cmay be monitored or recorded. In step 406, the system 100 and/or 200 maydetermine when a silent channel 324 d may become active. In step 408,the channel 324 d coefficients and/or parameters may be determined basedon the coefficients and or parameters on one or more of the activechannels 324 a, 324 b and 324 c. For example, coefficients or parametersfrom the active channel may be based on a copy of active channeltraining parameters, a weighted average of active channel trainingparameters, and/or a delta between active channel training parameters ata prior time and the active channel training parameters at a subsequenttime. In step 410, the coefficients and/or parameters may be adjustedfor the silent channels. The step 412 is an end step.

In an embodiment of the invention, an Ethernet link 112 may comprise aplurality of channels such as channels 224 and/or 324 wherein one ormore channels may be silent and one or more channels may be active. Inthis regard, training parameters from the one or more active channelsmay be utilized for determining and/or configuring training parametersfor the one or more silent channels. For example, training parametersfrom channels 324 a, 324 b and/or 324 c may be utilized to determine andconfigure training parameters on silent channel 324 d prior toactivating channel 324 d. Training parameters for one or more of thesilent channels such as channel 324 d may be determined based on copyingtraining parameters from the one or more active channels such as 324 a,234 b and 234 c. Moreover, determination of training parameters for theone or more silent channels may be based on a weighted average of theactive channel training parameters. In some embodiments of theinvention, a delta between active channel training parameters from aprior time and subsequent time may be utilized to determine a correctionfactor for modifying training parameters for a silent channel from aprior time. In this regard, the silent channel may be configured withthe modified prior time training parameters. In addition, silentchannels may be configured based on active channel training parametersand then subsequently may be trained. Accordingly, training parametersmay be configured for one or more of an echo canceler, a near-endcrosstalk canceler and a far-end canceler, for example within one ormore hybrid 226, corresponding to the Ethernet link 112.

Another embodiment of the invention may provide a machine-readablestorage, having stored thereon, a computer program having at least onecode section executable by a machine, thereby causing the machine toperform the steps as described herein for training an Ethernet channelbased on an active channel to support energy efficient Ethernetnetworks.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputer system or in a distributed fashion where different elements arespread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

What is claimed is:
 1. A method for networking, comprising: in acommunication link comprising a plurality of channels, wherein one ormore of a first subset of the plurality of channels is in a silent stateand one or more of a second subset of the plurality of channels is in anactive state, identifying a change in one or more training parametersfor one or more of the second subset of the plurality of channels from afirst point in time to a second point in time subsequent to the firstpoint in time, the one or more training parameters configuringcommunication over the one or more of the second subset of the pluralityof channels; and adjusting the one or more training parameters for theone or more of the first subset of the plurality of channels based onthe identified change.
 2. The method according to claim 1, wherein theadjusting comprises comprising adjusting the one or more trainingparameters for one or more of an echo canceler, a far-end crosstalkcanceler, and a near-end crosstalk canceler corresponding to thecommunication link.
 3. The method according to claim 1, wherein theadjusting comprises copying one or more training parameters for one ormore of the second subset of the plurality of channels for use by one ormore of the first subset of the plurality of channels.
 4. The methodaccording to claim 1, wherein the adjusting comprises determining one ormore training parameters for the one or more of the first subset of theplurality of channels based on a weighted average of one or moretraining parameters from one or more of the second subset of theplurality of channels.
 5. The method according to claim 1, wherein theadjusting comprises determining one or more training parameters for theone or more of the first subset of the plurality of channels based on adelta between the one or more training parameters from one or more ofthe second subset of the plurality of channels from the first point intime to the second point in time subsequent to the first point in time.6. The method according to claim 1, transitioning, at a point in timesubsequent to the adjustment, the one or more of the first subset of theplurality of channels from the silent state to the active state.
 7. Asystem for networking, the system comprising: one or more circuits in alink partner that is coupled to a communication link, the communicationlink including a plurality of channels, wherein one or more of a firstsubset of the plurality of channels is in a silent state and one or moreof a second subset of the plurality of channels is in an active state,the one or more circuits operable to: identify a change in one or moretraining parameters for one or more of the second subset of theplurality of channels from a first point in time to a second point intime subsequent to the first point in time, the one or more trainingparameters configuring communication over the one or more of the secondsubset of the plurality of channels; and adjust the one or more trainingparameters for the one or more of the first subset of the plurality ofchannels based on the identified change.
 8. The system according toclaim 7, wherein the one or more training parameters are for one or moreof an echo canceler, a far-end crosstalk canceler, and a near-endcrosstalk canceler corresponding to the communication link.
 9. Thesystem according to claim 7, wherein the adjustment is based on a copyof one or more training parameters for one or more of the second subsetof the plurality of channels.
 10. The system according to claim 7,wherein the adjustment is based on a weighted average of one or moretraining parameters from one or more of the second subset of theplurality of channels.
 11. The system according to claim 7, wherein theadjustment is based on a delta between the one or more trainingparameters from one or more of the second subset of the plurality ofchannels from the first point in time to the second point in timesubsequent to the first point in time.
 12. The system according to claim7, wherein the one or more circuits are further operable to transition,at a point in time subsequent to the adjustment, the one or more of thefirst subset of the plurality of channels from the silent state to theactive state.
 13. A non-transitory machine-readable storage havingstored thereon, a computer program having at least one code section fornetworking, the at least one code section being executable by a machinefor causing the machine to perform steps comprising: in a communicationlink comprising a plurality of channels, wherein one or more of a firstsubset of the plurality of channels is in a silent state and one or moreof a second subset of the plurality of channels is in an active state,identifying a change in one or more training parameters for one or moreof the second subset of the plurality of channels from a first point intime to a second point in time subsequent to the first point in time,the one or more training parameters configuring communication over theone or more of the second subset of the plurality of channels; andadjusting the one or more training parameters for the one or more of thefirst subset of the plurality of channels based on the identifiedchange.
 14. The non-transitory machine-readable storage according toclaim 13, wherein the adjusting comprises comprising adjusting the oneor more training parameters for one or more of an echo canceler, afar-end crosstalk canceler, and a near-end crosstalk cancelercorresponding to the communication link.
 15. The non-transitorymachine-readable storage according to claim 13, wherein the adjustingcomprises copying one or more training parameters for one or more of thesecond subset of the plurality of channels for use by one or more of thefirst subset of the plurality of channels.
 16. The non-transitorymachine-readable storage according to claim 13, wherein the adjustingcomprises determining one or more training parameters for the one ormore of the first subset of the plurality of channels based on aweighted average of one or more training parameters from one or more ofthe second subset of the plurality of channels.
 17. The non-transitorymachine-readable storage according to claim 13, wherein the adjustingcomprises determining one or more training parameters for the one ormore of the first subset of the plurality of channels based on a deltabetween the one or more training parameters from one or more of thesecond subset of the plurality of channels from the first point in timeto the second point in time subsequent to the first point in time. 18.The non-transitory machine-readable storage according to claim 13,transitioning, at a point in time subsequent to the adjustment, the oneor more of the first subset of the plurality of channels from the silentstate to the active state.